CN104508896B - Nonaqueous electrolytic solution and the electric energy storage device of the nonaqueous electrolytic solution is used - Google Patents

Abstract

The present invention provides a kind of nonaqueous electrolytic solution, has used the electric energy storage device of the nonaqueous electrolytic solution, the nonaqueous electrolytic solution is the nonaqueous electrolytic solution that electrolytic salt is dissolved with nonaqueous solvents, wherein, contain the 1 of 0.001~5 mass % in nonaqueous electrolytic solution, 3- dioxs, and the further at least one in the cyclic acid anhydride selected from specific phosphate compound, specific cyclic sulfonic acid ester compound and containing the side chain with allylic hydrogen containing 0.001~5 mass %.The nonaqueous electrolytic solution can improve the electrochemical properties under high temperature, and then can not only reduce the capacity sustainment rate after high temperature circulation experiment, moreover it is possible to reduce the increment rate of thickness of electrode.

Description

Non-aqueous electrolytic solution and electrical storage device using the non-aqueous electrolytic solution

technical field

The present invention relates to a non-aqueous electrolytic solution capable of improving electrochemical properties at high temperatures, and an electrical storage device using the non-aqueous electrolytic solution.

Background technique

In recent years, power storage devices, particularly lithium secondary batteries, have been widely used as power sources for electronic devices such as mobile phones and notebook computers, as well as power sources for electric vehicles and power storage. Batteries installed in these electronic devices and automobiles are likely to be used in high summer temperatures or in environments where electronic devices heat up. In addition, in thin electronic devices such as tablet terminals and ultrabooks, laminated batteries or square batteries in which laminated films such as aluminum laminated films are used as outer packaging parts are often used. However, these batteries are thin and Therefore, there is a problem that deformation is likely to occur due to slight expansion of the outer package member, and there is a problem that the deformation has a great influence on the electronic device.

Lithium secondary batteries are mainly composed of positive and negative electrodes containing materials that can intercalate and deintercalate lithium, non-aqueous electrolytes containing lithium salts and non-aqueous solvents. As non-aqueous solvents, ethylene carbonate (EC), ethylene carbonate, and Carbonates such as propyl ester (PC).

In addition, metal lithium, metal compounds capable of intercalating and deintercalating lithium (elemental metals, oxides, alloys with lithium, etc.), and carbon materials are known as negative electrodes for lithium secondary batteries. In particular, among carbon materials, non-aqueous electrolyte secondary batteries using carbon materials capable of intercalating and deintercalating lithium, such as coke and graphite (artificial graphite, natural graphite), have been widely put into practical use. The above-mentioned negative electrode materials intercalate and deintercalate lithium and electrons at the same extremely low potential as lithium metal, so especially at high temperatures, most solvents may be reduced and decomposed. Regardless of the type of negative electrode material, on the negative electrode The solvent in the electrolyte is partially reduced and decomposed, and the movement of lithium ions is hindered due to the deposition of decomposition products, the generation of gas, and the expansion of the electrode. Swelling causes problems such as battery deformation. Furthermore, for lithium secondary batteries using lithium metal or its alloys, metal simple substances such as tin or silicon, or oxides as negative electrode materials, we know that although the initial capacity is high, due to continuous micronization in the cycle, the negative electrode of carbon materials In contrast, the reductive decomposition of non-aqueous solvents is accelerated, especially at high temperatures, there are problems such as a significant decrease in battery performance such as battery capacity and cycle characteristics, and battery deformation due to expansion of the electrodes.

On the other hand, LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiFePO ₄ and other materials capable of intercalating and deintercalating lithium used as positive electrode materials are capable of intercalating and deintercalating lithium at a high voltage of 3.5 V or higher based on lithium. and electrons, so especially at high temperatures, most solvents are likely to be oxidized and decomposed. Regardless of the type of positive electrode material, the solvent in the electrolyte on the positive electrode is partially oxidized and decomposed. Due to the deposition of decomposition products and the generation of gas, The movement of lithium ions is hindered, and there is a problem that battery characteristics such as cycle characteristics are degraded.

In spite of the above situation, the multifunctionalization of electronic devices equipped with lithium secondary batteries is progressing, and the power consumption tends to increase. For this reason, the high capacity of lithium secondary batteries is constantly developing, and the volume occupied by the non-aqueous electrolyte in the battery is continuously reduced by increasing the density of the electrodes or reducing the excess space volume in the battery. Therefore, it is a situation in which battery performance at high temperatures tends to decrease due to decomposition of a small amount of non-aqueous electrolytic solution.

Patent Document 1 discloses that when a nonaqueous electrolyte secondary battery using an electrolyte solution containing 1,3-dioxane is stored in a charged state, it is possible to prevent the positive electrode active material from interacting with the nonaqueous electrolyte solution. The reaction makes the battery swell, and simultaneously the decline of the battery capacity of this non-aqueous electrolyte secondary battery can be suppressed. In addition, the following content is disclosed in Patent Document 2: the electrolytic solution containing triethylphosphonoacetate is continuously charged After the gas suppression and high-temperature storage characteristics have shown effects.

Patent Document 3 discloses that an electrolytic solution containing 1,3-dioxane and a chain sulfonate ester exhibits effects in cycle characteristics and high-temperature storage characteristics.

Patent Document 1: Japanese Unexamined Patent Publication No. 2008-235147

Patent Document 2: Japanese Patent Laid-Open No. 2008-262908

Patent Document 3: Japanese Patent Laid-Open No. 2009-140919

Contents of the invention

The problem to be solved by the present invention

The object of the present invention is to provide a non-aqueous electrolytic solution capable of improving the electrochemical characteristics at high temperature, thereby reducing not only the capacity retention rate after the high-temperature cycle test, but also the increase rate of the electrode thickness, and a battery using the same. equipment.

means of solving problems

The inventors of the present invention conducted detailed studies on the performance of the non-aqueous electrolytic solution of the above-mentioned patent documents.

As a result, although the battery of Patent Document 1 can prevent battery swelling by suppressing gas generation, it cannot be said to be sufficiently satisfactory for reducing the rate of increase in electrode thickness.

In addition, although the non-aqueous electrolyte solutions of Patent Documents 2 and 3 can improve the capacity retention rate after high-temperature cycles, they cannot be said to be sufficiently satisfactory for reducing the increase rate of electrode thickness in actual situations.

Therefore, the inventors of the present invention have repeatedly conducted intensive studies in order to solve the above-mentioned problems. As a result, they found that 1,3-dioxane is contained, and further, by adding a specific phosphoric acid ester compound, cyclic sulfonic acid, etc. At least one of an ester compound and a cyclic acid anhydride having a side chain having an allyl hydrogen can improve the capacity retention rate after high-temperature cycles and can reduce the increase rate of electrode thickness, thereby completing the present invention.

That is, the present invention provides the following (1) and (2).

(1) A nonaqueous electrolytic solution, characterized in that it is a nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent, and the nonaqueous electrolytic solution contains 0.001 to 5% by mass of 1,3-dioxane , and further contain 0.001 to 5% by mass of a phosphoric acid ester compound represented by the following general formula (I), a cyclic sulfonic ester compound represented by the general formula (II) and a ring containing a side chain having an allyl hydrogen At least one of the acid anhydrides.

(In the formula, R ¹ and R ² independently represent an alkyl group with 1 to 6 carbon atoms or a haloalkyl group with 1 to 6 carbon atoms in which at least one hydrogen atom is replaced by a halogen atom, and R ³ represents a carbon An alkyl group with 1 to 6 atoms, an alkenyl group with 2 to 6 carbon atoms, or an alkynyl group with ³ to ⁶ carbon atoms, R4 and R5 independently represent a hydrogen atom, a halogen atom or a carbon atom Alkyl groups with a number of 1 to 4.)

(In the formula, R ⁶ and R ⁷ independently represent a hydrogen atom, an alkyl group with 1 to 6 carbon atoms or a halogen atom in which at least one hydrogen atom may be replaced by a halogen atom, and X represents -CH(OR ⁸ )- Or -C(=O)-, R ⁸ represents formyl, alkylcarbonyl with 2 to 7 carbon atoms, alkenylcarbonyl with 3 to 7 carbon atoms, alkynyl with 3 to 7 carbon atoms carbonyl or an arylcarbonyl group with 7 to 13 carbon atoms. At least one hydrogen atom of R ⁸ may also be substituted by a halogen atom.)

(2) An electrical storage device comprising a positive electrode, a negative electrode, and a nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent, and the nonaqueous electrolytic solution contains 0.001 to 5% by mass of 1,3- Dioxane, and further containing 0.001 to 5% by mass of a phosphoric acid ester compound represented by the above general formula (I), a cyclic sulfonate compound represented by the above general formula (II), and a side compound having an allyl hydrogen At least one of chained cyclic anhydrides.

Invention effect

According to the present invention, it is possible to provide a non-aqueous electrolytic solution capable of improving the capacity retention rate after high-temperature cycles and reducing the increase rate of electrode thickness, and an electrical storage device such as a lithium battery using the non-aqueous electrolytic solution.

detailed description

〔Non-aqueous electrolyte solution〕

The non-aqueous electrolytic solution of the present invention is characterized in that it is a non-aqueous electrolytic solution in which an electrolyte salt is dissolved in a non-aqueous solvent, and the non-aqueous electrolytic solution contains 0.001 to 5% by mass of 1,3-dioxane, and further Containing 0.001 to 5% by mass of a phosphoric acid ester compound represented by the following general formula (I), a cyclic sulfonate compound represented by the general formula (II), and a cyclic acid anhydride containing a side chain having an allyl hydrogen at least one of .

The reason why the non-aqueous electrolytic solution of the present invention can greatly improve the electrochemical characteristics in a wide temperature range is unclear, but it is considered as follows.

The 1,3-dioxane used in the present invention decomposes on the negative electrode and forms a covering film, but when used alone, repeated charging and discharging under high temperature conditions will cause the dissolution and reformation of the covering film, so that the covering film will grow, The thickness of the electrodes is greatly increased. On the other hand, it has been found out that if the phosphoric acid ester compound represented by the general formula (I), the cyclic sulfonic acid ester compound represented by the general formula (II), and the cyclic acid anhydride containing a side chain having an allyl hydrogen are used in combination At least one kind can suppress the decomposition of 1,3-dioxane on the negative electrode, and at the same time rapidly form the above-mentioned compound with multiple reaction sites with 1,3-dioxane on the active point on the negative electrode The formed strong composite covering film has improved high-temperature cycle characteristics, and the growth of the covering film is suppressed, which can further suppress the increase in electrode thickness.

In the nonaqueous electrolytic solution of the present invention, the content of 1,3-dioxane is 0.001 to 5% by mass in the nonaqueous electrolytic solution. If the content is 5% by mass or less, the coating film is excessively formed on the electrode, and the high-temperature cycle characteristics are less likely to decrease. In addition, if the content is 0.001% by mass or more, the formation of the coating film is sufficient, and the improvement effect of high-temperature cycle characteristics is small. improve. The content is preferably 0.01% by mass or more, more preferably 0.1% by mass or more in the nonaqueous electrolytic solution. In addition, the upper limit thereof is preferably 4% by mass or less, more preferably 2% by mass or less.

The phosphoric acid ester compound contained in the nonaqueous electrolytic solution of the present invention is represented by the following general formula (I).

(In the formula, R ¹ and R ² independently represent an alkyl group with 1 to 6 carbon atoms or a haloalkyl group with 1 to 6 carbon atoms in which at least one hydrogen atom is replaced by a halogen atom, and R ³ represents a carbon An alkyl group with 1 to 6 atoms, an alkenyl group with 2 to 6 carbon atoms, or an alkynyl group with ³ to ⁶ carbon atoms, R4 and R5 independently represent a hydrogen atom, a halogen atom or a carbon atom Alkyl groups with a number of 1 to 4.)

Specific examples ^of R1 and R2 include linear alkyl groups such as methyl, ethyl, n ^- propyl, n-butyl, n-pentyl, n-hexyl, isopropyl, sec-butyl, tert-butyl Branched alkyl groups such as radicals and tert-amyl groups, fluoroalkyl groups such as fluoromethyl groups and 2,2,2-trifluoroethyl groups in which a part of hydrogen atoms are replaced by fluorine atoms, etc.

Among these, methyl, ethyl, n-propyl, isopropyl or 2,2,2-trifluoroethyl is preferred, and methyl or ethyl is more preferred.

Specific examples of ^R include linear alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, isopropyl, sec-butyl, tert-butyl, tert- Pentyl and other branched alkyl, 2-propenyl, 2-butenyl, 3-butenyl, 4-pentenyl, 5-hexenyl, 2-methyl-2-propenyl, 3- Alkenyl such as methyl-2-butenyl, 2-propynyl, 2-butynyl, 3-butynyl, 4-pentynyl, 5-hexynyl, 1-methyl-2- Alkynyl groups such as propynyl and 1,1-dimethyl-2-propynyl, etc.

Among these, methyl, ethyl, n-propyl, isopropyl, 2-propenyl, 2-butenyl, 2-propynyl, 2-butynyl or 1-methyl-2-prop Alkynyl, more preferably methyl, ethyl, 2-propenyl, 2-propynyl or 1-methyl-2-propynyl.

As specific examples of ^R4 and R5, linear alkyl groups such as hydrogen atoms, fluorine atoms, chlorine atoms, methyl groups, ethyl groups, n ^- propyl groups, n-butyl groups, isopropyl groups, sec-butyl groups, etc. branched alkyl such as base, tert-butyl, etc.

Among these, a hydrogen atom, a fluorine atom, a methyl group, an ethyl group, an n-propyl group or an isopropyl group is preferable, and a hydrogen atom, a fluorine atom, a methyl group or an ethyl group is more preferable.

Examples of the phosphoric acid ester compound represented by the general formula (I) include the following compounds and the like.

Among these, it is preferable to have the above-mentioned I-2, I-4 to I-6, I-14, I-18, I-21 to I-40, I-42 to I-50, I-52 to I-54 The compound of the structure, more preferably 2-(diethoxyphosphoryl) ethyl acetate (compound I-2), 2-(dimethoxyphosphoryl) acetate 2-propynyl ester (compound I-4), 2-(diethoxyphosphoryl) methyl acetate (compound I-5), 2-(diethoxyphosphoryl) ethyl acetate (compound I-6), 2-(diethoxyphosphoryl) 2-propenyl acetate (compound I-14), 2-(diethoxyphosphoryl)acetate 2-propynyl ester (compound I-18), 2-(diethoxyphosphoryl)acetate 1-methyl -2-propynyl ester (compound I-21), 2-(dimethoxyphosphoryl)propionate 2-propynyl ester (compound I-30), 2-(diethoxyphosphoryl)propionate 2 -propynyl ester (compound I-34), 2-(dimethoxyphosphoryl)-2-fluoroethyl acetate (compound I-37), 2-(diethoxyphosphoryl-2-fluoro)acetic acid Methyl ester (compound I-39), 2-(diethoxyphosphoryl)-2-fluoroacetic acid ethyl ester (compound I-40), 2-(diethoxyphosphoryl)-2-fluoroacetic acid 2- Propyl ester (compound I-42), 2-(diethoxyphosphoryl)-2-fluoroacetate 2-propynyl ester (compound I-43), 2-(diethoxyphosphoryl)-2-fluoro 1-methyl-2-propynyl acetate (compound I-44), ethyl 2-(dimethoxyphosphoryl)-2,2-difluoroacetate (compound I-47), 2-(diethyl Oxyphosphoryl)-2,2-difluoroacetic acid methyl ester (compound I-49), 2-(diethoxyphosphoryl)-2,2-difluoroacetic acid ethyl ester (compound I-50), 2 -(diethoxyphosphoryl)-2,2-difluoroacetic acid 2-propenyl ester (compound I-52), 2-(diethoxyphosphoryl)-2,2-difluoroacetic acid 2-propyne ester (compound I-53), 2-(diethoxyphosphoryl)-2,2-difluoroacetic acid 1-methyl-2-propynyl ester (compound I-54).

The cyclic sulfonate compound contained in the nonaqueous electrolytic solution of the present invention is represented by the following general formula (II).

(In the formula, R ⁶ and R ⁷ independently represent a hydrogen atom, an alkyl group with 1 to 6 carbon atoms or a halogen atom in which at least one hydrogen atom may be replaced by a halogen atom, and X represents -CH(OR ⁸ )- Or -C(=O)-, R ⁸ represents formyl, alkylcarbonyl with 2 to 7 carbon atoms, alkenylcarbonyl with 3 to 7 carbon atoms, alkynyl with 3 to 7 carbon atoms Carbonyl or an arylcarbonyl group with 7 to 13 carbon atoms, at least one hydrogen atom of R ⁸ may also be substituted by a halogen atom.)

R ⁶ and R ⁷ are more preferably a hydrogen atom, an alkyl group with 1 to 4 carbon atoms that may be replaced by a halogen atom at least one hydrogen atom, or a halogen atom, more preferably a hydrogen atom, and at least one hydrogen atom may be replaced by a halogen atom. An alkyl group having 1 or 2 carbon atoms replaced by an atom.

R ⁸ is preferably a formyl group, an alkylcarbonyl group having 2 to 7 carbon atoms, or an alkenylcarbonyl group having 3 to 5 carbon atoms, more preferably a formyl group or an alkylcarbonyl group having 2 to 5 carbon atoms.

Examples of the cyclic sulfonate compound represented by the general formula (II) include the following compounds and the like.

Among these, compounds having the structures of II-1 to II-3, II-6, II-8, II-9, II-11, II-22, II-24, and II-25 are preferred, and 2 , 2-dioxide-1,2-oxathiolane-4-ol acetate (compound II-2), 2,2-dioxide-1,2-oxathiolane-4- Alcohol propionate (compound II-3) and 5-methyl-1,2-oxathiolane-4-one 2,2-dioxide (compound II-22) or 5,5-dimethyl Base-1,2-oxathiolan-4-one 2,2-dioxide (compound II-24).

The cyclic acid anhydride having a side chain having an allyl hydrogen contained in the nonaqueous electrolytic solution of the present invention contains a main body of the cyclic acid anhydride and a side chain having an allyl hydrogen bonded to the main body of the cyclic acid anhydride.

The main body of the cyclic acid anhydride is preferably a cyclic acid anhydride having 4 to 5 carbon atoms, more preferably succinic anhydride.

The side chain having allyl hydrogen is preferably a straight chain or branched hydrocarbon group having 3 to 12 carbon atoms, more preferably 3 to 10 carbon atoms.

Here, "allyl hydrogen" means, for example, in the case of an allyl group represented by CH ₂ =CH-CH ₂ - on the right, two hydrogens bonded to the allyl carbon next to the double bond, " Having an allyl hydrogen" means having at least one of the two hydrogens. In the compound of the present invention, the number of allyl hydrogens is preferably 1-4, more preferably 1 or 2, even more preferably 2.

In the cyclic acid anhydride having a side chain having the above-mentioned allyl hydrogen, the allyl carbon is preferably present between the double bond and the cyclic acid anhydride, more preferably directly bonded to both the double bond and the cyclic acid anhydride.

In addition, the number of hydrogen atoms directly bonded to the double bond in the side chain is preferably 2 or 3, more preferably 3, that is, the terminal double bond. This is because it is considered that by containing allyl hydrogen and a terminal double bond, it is possible to easily and rapidly form a strong composite coating when used together with 1,3-dioxane.

The side chain having an allyl hydrogen may be cyclic, linear or branched, and may be substituted with an alkyl group, an aryl group, or a group containing a heteroatom or the like.

Specific examples of side chains having allyl hydrogen include allyl, 3-buten-2-yl, 1-penten-3-yl, 1-hexen-3-yl, 1 -Hepten-3-yl, 1-octen-3-yl, 1-nonen-3-yl, 2-buten-1-yl, 3-methyl-2-buten-1-yl, 2 , 3-Dimethyl-2-buten-1-yl, 4-methyl-1-penten-3-yl, 4-methyl-1-hexen-3-yl, 4,4-dimethyl Base-1-penten-3-yl, 3-buten-1-yl, 3-penten-2-yl, 4-penten-1-yl, 5-hexen-2-yl, 2-methyl Allyl, 2-methyl-1-penten-3-yl, 2,4-dimethyl-1-penten-3-yl, 2,3-dimethyl-3-buten-2 -yl, 3-methyl-3-buten-1-yl, 4-methyl-4-penten-2-yl, etc.

Among these, allyl, 1-penten-3-yl, 1-hexen-3-yl, 1-hepten-3-yl, 1-octen-3-yl, 1-nonen- 3-yl, 3-buten-2-yl, 2-methylallyl, 3-methyl-3-buten-2-yl, more preferably allyl, 3-buten-2-yl, 2-methylallyl, 3-methyl-3-buten-2-yl.

As specific examples of the above-mentioned cyclic acid anhydrides, 2-allyl succinic anhydride, 2-(3-buten-2-yl)succinic anhydride, 2-(1-penten-3-yl)succinic anhydride, 2-(1-penten-3-yl)succinic anhydride, Anhydride, 2-(1-hexen-3-yl)succinic anhydride, 2-(1-hepten-3-yl)succinic anhydride, 2-(1-octen-3-yl)succinic anhydride, 2-( 1-nonen-3-yl)succinic anhydride, 2-(2-buten-1-yl)succinic anhydride, 2-(3-methyl-2-buten-1-yl)succinic anhydride, 2-( 2,3-Dimethyl-2-buten-1-yl)succinic anhydride, 2-(4-methyl-1-penten-3-yl)succinic anhydride, 2-(4-methyl-1- Hexen-3-yl)succinic anhydride, 2-(4,4-dimethyl-1-penten-3-yl)succinic anhydride, 2-(3-buten-1-yl)succinic anhydride, 2- (3-penten-2-yl)succinic anhydride, 2-(4-penten-1-yl)succinic anhydride, 2-(5-hexen-2-yl)succinic anhydride, 2-(2-methyl Allyl)succinic anhydride, 2-(2-methyl-1-penten-3-yl)succinic anhydride, 2-(2,4-dimethyl-1-penten-3-yl)succinic anhydride, 2-(2,3-Dimethyl-3-buten-2-yl)succinic anhydride, 2-(3-methyl-3-buten-1-yl)succinic anhydride, 2-(4-methyl -4-penten-2-yl) succinic anhydride, etc.

Among these, more preferably selected from 2-allyl succinic anhydride, 2-(1-penten-3-yl) succinic anhydride, 2-(1-hexen-3-yl) succinic anhydride, 2-(1 -Hepten-3-yl)succinic anhydride, 2-(1-octen-3-yl)succinic anhydride, 2-(1-nonen-3-yl)succinic anhydride, 2-(3-butene-2 -base) succinic anhydride, 2-(2-methallyl) succinic anhydride and 2-(3-methyl-3-buten-2-yl) succinic anhydride, more preferably selected from 2 -Allyl succinic anhydride, 2-(3-buten-2-yl)succinic anhydride, 2-(2-methylallyl)succinic anhydride and 2-(3-methyl-3-butene-2 -base) at least one of succinic anhydrides.

In the non-aqueous electrolytic solution of the present invention, the non-aqueous electrolytic solution contains phosphoric acid ester compounds represented by general formula (I), cyclic sulfonic ester compounds represented by general formula (II) and compounds containing allyl hydrogen The content of at least one kind of cyclic acid anhydrides in the side chain is 0.001 to 5% by mass in the nonaqueous electrolytic solution. If the content is 5% by mass or less, the coating film is excessively formed on the electrode, and the high-temperature cycle characteristics are less likely to decrease. In addition, if the content is 0.001% by mass or more, the formation of the coating film is sufficient, and the improvement effect of high-temperature cycle characteristics is small. improve. The content is preferably 0.01% by mass or more, more preferably 0.1% by mass or more in the nonaqueous electrolytic solution, and the upper limit thereof is preferably 4% by mass or less, more preferably 2% by mass or less.

In addition, the mixing ratio (weight ratio) of cyclic acid anhydride having a side chain having allyl hydrogen: 1,3-dioxane is preferably 2:98 to 80:20, more preferably 5:95 to 40:60 , and more preferably 10:90 to 30:70.

Furthermore, it is more preferable to use two or more selected from the group consisting of phosphoric acid ester compounds represented by general formula (I), cyclic sulfonic acid ester compounds represented by general formula (II), and cyclic acid anhydrides containing side chains having allyl hydrogen. and use.

In the non-aqueous electrolytic solution of the present invention, by being selected from the phosphate ester compound represented by general formula (I), the cyclic sulfonic ester compound represented by general formula (II) and the cyclic compound containing a side chain with allyl hydrogen Combining at least one of acid anhydrides and 1,3-dioxane with the following non-aqueous solvents and electrolyte salts can increase the capacity retention rate after high-temperature cycles, and exhibit the special effect of reducing the increase rate of electrode thickness .

〔Non-aqueous solvent〕

As the non-aqueous solvent used in the non-aqueous electrolytic solution of the present invention, one or two or more selected from cyclic carbonates, chain esters, ethers, amides, sulfones and lactones can be listed, preferably containing at least 1 A cyclic carbonate, more preferably contains both cyclic carbonate and chain ester.

In addition, the term chain ester is used as a concept including chain carbonate and chain carboxylate.

Examples of cyclic carbonates include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 4-fluoro-1,3 -dioxolane-2-one (FEC), trans or cis-4,5-difluoro-1,3-dioxolane-2-one (hereinafter collectively referred to as " DFEC"), vinylene carbonate (VC), vinylethylene carbonate (VEC) and 4-ethynyl-1,3-dioxolane-2-one (EEC) or both More than one, more preferably selected from ethylene carbonate, propylene carbonate, 4-fluoro-1,3-dioxolan-2-one, vinylene carbonate and 4-ethynyl-1,3- One or two or more kinds of dioxolan-2-one (EEC).

In addition, if at least one of the above-mentioned cyclic carbonates having unsaturated bonds such as carbon-carbon double bonds and carbon-carbon triple bonds or fluorine atoms is used, the low-temperature load characteristics after high-temperature charging and storage are further improved, so it is preferred It is more preferable to include both a cyclic carbonate containing an unsaturated bond such as a carbon-carbon double bond and a carbon-carbon triple bond and a cyclic carbonate having a fluorine atom. The cyclic carbonates containing unsaturated bonds such as carbon-carbon double bonds and carbon-carbon triple bonds are more preferably VC, VEC, and EEC, and the cyclic carbonates having fluorine atoms are more preferably FEC and DFEC.

The content of cyclic carbonates having unsaturated bonds such as carbon-carbon double bonds and carbon-carbon triple bonds is preferably 0.07% by volume or more, more preferably 0.2% by volume or more, and even more preferably 0.7% by volume relative to the total volume of the non-aqueous solvent. In addition, as the upper limit, it is preferably 7 volume % or less, more preferably 4 volume % or less, and even more preferably 2.5 volume % or less. In this case, Li ion permeability at low temperatures can be It is preferable to further increase the stability of the cover film during high-temperature storage.

The content of the cyclic carbonate having a fluorine atom is preferably 0.07% by volume or more, more preferably 4% by volume or more, and even more preferably 7% by volume or more with respect to the total volume of the non-aqueous solvent, and the upper limit thereof is preferably 35% by volume. Volume % or less, more preferably 25 volume % or less, even more preferably 15 volume % or less, at this time, the stability of the cover film during high temperature storage can be further increased without impairing the Li ion permeability at low temperature. is preferred.

When the non-aqueous solvent contains both cyclic carbonates having unsaturated bonds such as carbon-carbon double bonds and carbon-carbon triple bonds and cyclic carbonates having fluorine atoms, the carbon-carbon double bonds, carbon-carbon The content of the cyclic carbonate having an unsaturated bond such as a triple bond is preferably 0.2% by volume or more, more preferably 3% by volume or more, and even more preferably 7% by volume or more, with respect to the content of the cyclic carbonate having a fluorine atom. The upper limit is preferably 40% by volume or less, more preferably 30% by volume or less, and even more preferably 15% by volume or less. At this time, the coverage during high-temperature storage can be further increased without impairing the Li ion permeability at low temperature. Membrane stability is thus particularly preferred.

In addition, when the non-aqueous solvent contains ethylene carbonate, propylene carbonate, or both ethylene carbonate and propylene carbonate, the resistance of the coating film formed on the electrode becomes small, which is preferable. The content of ethylene carbonate, propylene carbonate, or both ethylene carbonate and propylene carbonate is preferably 3% by volume or more relative to the total volume of the nonaqueous solvent, more preferably 5% by volume or more, even more preferably 7% by volume or more, and the upper limit thereof is preferably 45% by volume or less, more preferably 35% by volume or less, and still more preferably 25% by volume or less.

One of these solvents can be used, and when two or more of them are used in combination, the electrochemical characteristics in a wide temperature range are further improved, so it is preferable, and it is particularly preferable to use in combination of three or more. As a preferred combination of the aforementioned cyclic carbonates, EC and PC, EC and VC, PC and VC, VC and FEC, EC and FEC, PC and FEC, FEC and DFEC, EC and DFEC, PC and DFEC, VC and DFEC, VEC and DFEC, VC and EEC, EC and EEC, EC and PC and VC, EC and PC and FEC, EC and VC and FEC, EC and VC and VEC, EC and VC and EEC, EC and EEC and FEC, PC and VC and FEC, EC and VC and DFEC, PC and VC and DFEC, EC and PC and VC and FEC, EC and PC and VC and DFEC, etc. Among the above combinations, EC and VC, EC and FEC, PC and FEC, EC and PC and VC, EC and PC and FEC, EC and VC and FEC, EC and VC and EEC, EC and EEC and FEC, PC are more preferred Combined with VC and FEC, EC and PC and VC and FEC, etc.

As chain esters, preferably asymmetric chain esters such as methyl ethyl carbonate (MEC), methyl propyl carbonate (MPC), methyl isopropyl carbonate (MIPC), methyl butyl carbonate, ethyl propyl carbonate, etc. Carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, dibutyl carbonate and other symmetrical chain carbonates, methyl trimethyl acetate, ethyl trimethyl acetate, three trimethyl acetate such as propyl methyl acetate, chain carboxylate such as methyl propionate, ethyl propionate, methyl acetate, ethyl acetate, etc.

When using a negative electrode with a charging potential of a fully charged state lower than 1V on a Li basis, among the above-mentioned chain esters, preferably selected from dimethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, A chain ester having a methyl group among methyl butyl carbonate, methyl propionate, methyl acetate, and ethyl acetate, particularly preferably a chain carbonate ester having a methyl group. This is because the decomposition on the negative electrode does not proceed easily, and capacity deterioration can be suppressed.

Moreover, when using the chain carbonate ester which has a methyl group, it is preferable to use 2 or more types. Furthermore, it is more preferable to contain both a symmetrical chain carbonate and an asymmetric chain carbonate, and it is still more preferable that content of a symmetrical chain carbonate is larger than an asymmetric chain carbonate.

The content of the chain ester is not particularly limited, but is preferably used within a range of 60 to 90% by volume based on the total volume of the nonaqueous solvent. If the content is more than 60% by volume, the effect of reducing the viscosity of the non-aqueous electrolytic solution cannot be fully obtained, and if the content is less than 90% by volume, the conductivity of the non-aqueous electrolytic solution can be fully improved, and the electrical conductivity in a wide temperature range The chemical properties are improved, and thus the above-mentioned range is preferable.

Moreover, when using chain carbonate, it is preferable to use 2 or more types. Furthermore, it is more preferable to contain both a symmetrical chain carbonate and an asymmetric chain carbonate, and it is still more preferable that content of a symmetrical chain carbonate is larger than an asymmetric chain carbonate.

The proportion of the volume of the symmetrical chain carbonate in the chain carbonate is preferably 51% by volume or more, more preferably 55% by volume or more. The upper limit is more preferably 95% by volume or less, and still more preferably 85% by volume or less. Dimethyl carbonate is particularly preferably contained in the symmetrical chain carbonate. In addition, the asymmetric chain carbonate more preferably contains a methyl group, and is particularly preferably ethyl methyl carbonate.

In the above case, the high-temperature cycle characteristics can be further improved, which is preferable.

From the viewpoint of improving the electrochemical characteristics in a wide temperature range, the ratio of cyclic carbonate to chain ester, that is, cyclic carbonate: chain ester (volume ratio), is preferably 10:90 to 45:55, more preferably 15:85 to 40:60, more preferably 20:80 to 35:65.

As other nonaqueous solvents, cyclic ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, 1,2-dioxane, etc. Chain ethers such as methoxyethane, 1,2-diethoxyethane, 1,2-dibutoxyethane, amides such as dimethylformamide, sulfones such as sulfolane, γ-butyrolactone, One or two or more kinds of lactones such as γ-valerolactone and α-angelica lactone.

〔Electrolyte salt〕

As the electrolyte salt used in the present invention, the following lithium salts are preferably mentioned.

(lithium salt)

As the electrolyte salt used in the present invention, the following lithium salts are preferably mentioned.

As lithium salts, inorganic lithium salts such as LiPF ₆ , LiPO ₂ F ₂ , Li ₂ PO ₃ F, LiBF ₄ , LiClO ₄ , LiSO ₃ F; LiN(SO ₂ F) ₂ , LiN(SO ₂ CF ₃ ) ₂ , LiN(SO ₂ C ₂ F ₅ ) ₂ , LiCF ₃ SO ₃ , LiC(SO ₂ CF ₃ ) ₃ , LiPF ₄ (CF ₃ ) ₂ , LiPF ₃ (C ₂ F ₅ ) ₃ , LiPF ₃ ( CF ₃ ) ₃ , LiPF ₃ (iso-C ₃ F ₇ ) ₃ , LiPF ₅ (iso-C ₃ F ₇ ) chain lithium salts containing fluoroalkyl groups; and (CF ₂ ) ₂ (SO ₂ ) ₂ NLi, (CF ₂ ) ₃ (SO ₂ ) ₂ NLi and other cyclic lithium salts containing fluoroalkylene chains; bis[oxalate-O,O']lithium borate (LiBOB) or difluoro[oxalate -O,O']lithium borate, difluorobis[oxalate-O,O']lithium phosphate (LiPFO) and tetrafluoro[oxalate-O,O']lithium phosphate with oxalate complex as anion Lithium salts, these electrolyte salts can be used alone or in combination of two or more.

Among these, LiPF ₆ , LiBF ₄ , LiPO ₂ F ₂ , Li ₂ PO ₃ F, LiSO ₃ F, LiN(SO ₂ F) ₂ , LiN(SO ₂ CF ₃ ) ₂ , LiN(SO ₂ C ₂ F ₅ ) ₂ , lithium bis[oxalate-O,O']borate (LiBOB), lithium difluorobis[oxalate-O,O']phosphate (LiPFO), and tetrafluoro[oxalate-O,O '] one or more of lithium phosphate, more preferably containing LiPF ₆ , LiBF ₄ , LiPO ₂ F ₂ , LiSO ₃ F, LiN(SO ₂ CF ₃ ) ₂ , LiN(SO ₂ F) ₂ , One or more of bis[oxalato-O,O']lithium borate and difluorobis[oxalato-O,O']lithium phosphate (LiPFO).

The concentration of the lithium salt is usually preferably 0.3M or higher, more preferably 0.7M or higher, and still more preferably 1.1M or higher relative to the above-mentioned non-aqueous solvent. In addition, the upper limit thereof is preferably 2.5M or less, more preferably 2.0M or less, and still more preferably 1.6M or less.

〔Manufacture of non-aqueous electrolytic solution〕

The non-aqueous electrolytic solution of the present invention, for example, can be obtained by the following method: mixing the above-mentioned non-aqueous solvent, adding 1,3-dioxane and a compound selected from the general formula ( At least one of a phosphoric acid ester compound represented by I), a cyclic sulfonic acid ester compound represented by general formula (II), and a cyclic acid anhydride having a side chain having an allyl hydrogen.

At this time, as the non-aqueous solvent used and the compound added to the non-aqueous electrolytic solution, it is preferable to use a compound that has been previously purified to minimize impurities within a range that does not significantly reduce productivity.

The non-aqueous electrolytic solution of the present invention can be used in the first and second power storage devices described below. As the non-aqueous electrolyte, not only liquid non-aqueous electrolytes but also gelled non-aqueous electrolytes can be used. Furthermore, the nonaqueous electrolytic solution of the present invention can also be used as a solid polymer electrolyte.

Among these, it is preferable to use a lithium salt as an electrolyte salt for the first storage device (that is, for a lithium battery) or for a second storage device (that is, for a lithium ion capacitor), and it is more preferable to use it for a lithium battery. For lithium secondary batteries.

[The first power storage device (lithium battery)]

The lithium battery of the present invention is a general term for a lithium primary battery and a lithium secondary battery. In addition, in this specification, the term lithium secondary battery is used as a concept including all lithium ion secondary batteries. The lithium battery of the present invention comprises a positive electrode, a negative electrode, and the above-mentioned non-aqueous electrolytic solution in which an electrolyte salt is dissolved in a non-aqueous solvent. Constituent members such as a positive electrode and a negative electrode other than the non-aqueous electrolytic solution can be used without particular limitation.

For example, as a positive electrode active material for a lithium secondary battery, a composite metal oxide containing lithium and one or two or more selected from cobalt, manganese, and nickel is used. These positive electrode active materials may be used alone or in combination of two or more.

Examples of such lithium composite metal oxides include those selected from LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiCo _1-x Ni _x O ₂ (0.01<x<1), LiCo _1/3 Ni _1/3 One or more of Mn _1/3 O ₂ , LiNi _1/2 Mn _3/2 O ₄ , LiCo _0.98 Mg _0.02 O ₂ . In addition, LiCoO ₂ and LiMn ₂ O ₄ , LiCoO ₂ and LiNiO ₂ , and LiMn ₂ O ₄ and LiNiO ₂ may be used in combination.

In addition, in order to improve safety and cycle characteristics during overcharge, it can be used at a charge potential of 4.3 V or higher, and a part of the lithium mixed metal oxide may be substituted with another element. For example, a part of cobalt, manganese, and nickel may be treated with at least one or more elements of Sn, Mg, Fe, Ti, Al, Zr, Cr, V, Ga, Zn, Cu, Bi, Mo, La, etc. Substitution, a part of O may be replaced with S or F, or compounds containing these other elements may also be covered.

Among these, lithium composite metal oxides such as LiCoO ₂ , LiMn ₂ O ₄ , and LiNiO ₂ , which can be used when the charging potential of the positive electrode in a fully charged state is 4.3 V or more based on Li, are preferable, and LiCo ₁ is more preferable. _-X M _X O ₂ (Wherein, M is one or two or more elements selected from Sn, Mg, Fe, Ti, Al, Zr, Cr, V, Ga, Zn, Cu, 0.001≤X≤0.05 ), LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ , LiNi _0.5 Mn _0.3 Co _0.2 O ₂ , LiNi _0.85 Co _0.10 Al _0.05 O ₂ , LiNi _1/2 Mn _3/2 O ₄ , Li ₂ MnO ₃ A lithium composite metal oxide that can be used at 4.4V or higher, such as a solid solution with LiMO ₂ (M is a transition metal such as Co, Ni, Mn, Fe). If a lithium composite metal oxide that can work at a high charging voltage is used, it is easy to reduce the electrochemical characteristics in a particularly wide temperature range due to the reaction with the electrolyte during charging, but the lithium secondary battery of the present invention can suppress these decrease in electrochemical properties.

Furthermore, lithium-containing olivine-type phosphate can also be used as the positive electrode active material. In particular, lithium-containing olivine-type phosphate containing one or two or more selected from iron, cobalt, nickel, and manganese is preferable. Specific examples thereof include LiFePO ₄ , LiCoPO ₄ , LiNiPO ₄ , LiMnPO ₄ , and the like.

A part of these lithium-containing olivine-type phosphates may be replaced with other elements, and a part of iron, cobalt, nickel, and manganese may be replaced with an element selected from the group consisting of Co, Mn, Ni, Mg, Al, B, Ti, V, Nb, and Cu. , Zn, Mo, Ca, Sr, W, Zr, etc., can be replaced with one or more elements, and can also be covered with a compound or carbon material containing these other elements. Among them, LiFePO ₄ or LiMnPO ₄ is preferable.

In addition, lithium-containing olivine-type phosphate can also be used after being mixed with the above-mentioned positive electrode active material, for example.

In addition, examples of positive electrodes for lithium primary batteries include CuO, Cu ₂ O, Ag ₂ O, Ag ₂ CrO ₄ , CuS, CuSO ₄ , TiO ₂ , TiS ₂ , SiO ₂ , SnO, V ₂ O ₅ , V ₆ O ₁₂ , VO _x , Nb ₂ O ₅ , Bi ₂ O ₃ , Bi ₂ Pb ₂ O ₅ , Sb ₂ O ₃ , CrO ₃ , Cr ₂ O ₃ , MoO ₃ , WO ₃ , SeO ₂ , MnO ₂ , Mn ₂ O ₃ , Fe ₂ O ₃ , FeO, Fe ₃ O ₄ , Ni ₂ O ₃ , NiO, CoO ₃ , CoO, etc. Oxide or chalcogen compound of one or more metal elements, SO ₂ , SOCl ₂ , etc. Sulfur compounds, fluorinated carbon (fluorinated graphite) represented by the general formula (CF _x ) _n , and the like. Among them, MnO ₂ , V ₂ O ₅ , graphite fluoride, and the like are preferable.

The conductive agent for the positive electrode is not particularly limited as long as it is an electron-conductive material that does not cause chemical changes. For example, one or two or more carbons selected from natural graphite (flaky graphite, etc.), graphite such as artificial graphite, acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black Black and so on. In addition, graphite and carbon black may be appropriately mixed and used. The amount of the conductive agent added to the positive electrode mixture is preferably 1 to 10% by mass, more preferably 2 to 5% by mass.

The positive electrode can be made by the following method: the above-mentioned positive electrode active material and conductive agents such as acetylene black, carbon black and polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), styrene and butadiene copolymer ( SBR), acrylonitrile and butadiene copolymer (NBR), carboxymethyl cellulose (CMC), ethylene-propylene terpolymer and other binders are mixed, and 1-methyl-2-pyrrolidone is added to it Boiling-point solvents are kneaded to make a positive electrode mixture, and then the positive electrode mixture is coated on the aluminum foil of the current collector or a stainless steel strip, etc., dried and press-molded. Heat treatment under vacuum for about 2 hours.

The density of the part of the positive electrode other than the current collector is generally 1.5 g/cm ³ or more, in order to further increase the capacity of the battery, it is preferably 2 g/cm ³ or more, more preferably 3 g/cm ³ or more, and even more preferably 3.6 g /cm ³ or more. In addition, the upper limit thereof is preferably 4 g/cm ³ or less.

As the negative electrode active material for lithium secondary batteries, carbon materials selected from lithium metal, lithium alloy, and capable of intercalating and deintercalating lithium [easy graphitizable carbon, difficult graphite with a crystal plane distance of (002) plane of 0.37 nm or more can be used. carbonized carbon, graphite with a (002) plane distance of 0.34nm or less], tin (single substance), tin compounds, silicon (single substance), silicon compounds, lithium titanate compounds such as Li ₄ Ti ₅ O ₁₂ , etc. One kind is used alone, or two or more kinds are used in combination.

Among these, it is more preferable to use highly crystalline carbon materials such as artificial graphite or natural graphite in terms of the intercalation and deintercalation capabilities of lithium ions, and it is particularly preferable to use a lattice plane (002) with a crystal plane distance (d ₀₀₂ ) of 0.340 A carbon material having a graphite-type crystal structure of nm (nano) or less, especially 0.335-0.337 nm.

By using artificial graphite particles having a massive structure in which a plurality of flat graphite particles are assembled or combined non-parallel to each other or by repeatedly applying compressive force, frictional force, shearing force, etc. to flaky natural graphite particles Graphite particles obtained by mechanical action and spheroidization treatment, so that the density of the part of the negative electrode other than the current collector is press-formed to a density of 1.5 g/ ^cm3 or more from the X-ray diffraction of the negative electrode sheet When the ratio I(110)/I(004) of the peak intensity I(110) of the (110) plane of the obtained graphite crystal to the peak intensity I(004) of the (004) plane reaches 0.01 or more, at a wider temperature The electrochemical characteristics in the range are improved, so it is preferable, more preferably 0.05 or more, particularly preferably 0.1 or more. In addition, excessive treatment may lower the crystallinity and lower the discharge capacity of the battery, so the upper limit is preferably 0.5 or less, more preferably 0.3 or less.

In addition, when a highly crystalline carbon material (core material) is covered with a carbon material with lower crystallinity than the core material, the electrochemical characteristics in a wide temperature range become more favorable, which is preferable. The crystallinity of the covered carbon material can be confirmed by TEM.

If a highly crystalline carbon material is used, it will react with the non-aqueous electrolyte during charging, and the increase in interface resistance will tend to reduce the electrochemical characteristics at low or high temperatures. However, the lithium secondary battery of the present invention has a wide temperature range. The electrochemical properties are good.

In addition, metal compounds capable of intercalating and deintercalating lithium as the negative electrode active material include Si, Ge, Sn, Pb, P, Sb, Bi, Al, Ga, In, Ti, Mn, Fe, Co, Ni , Cu, Zn, Ag, Mg, Sr, Ba and other metal elements at least one compound. These metal compounds can be used in any form such as elemental substance, alloy, oxide, nitride, sulfide, boride, and alloy with lithium, but due to any form of elemental substance, alloy, oxide, and alloy with lithium It is preferable because a high capacity can be achieved. Among them, it is preferable to contain at least one element selected from Si, Ge, and Sn, and it is particularly preferable to contain at least one element selected from Si and Sn, because the capacity of the battery can be increased.

The negative electrode can be made by the following method: use the same conductive agent, binder, and high-boiling point solvent as the above-mentioned positive electrode to knead to make a negative electrode mixture, and then apply the negative electrode mixture to the copper foil of the current collector Wait, after drying and press molding, heat treatment at a temperature of about 50°C to 250°C under vacuum for about 2 hours.

The density of the part of the negative electrode other than the current collector is usually 1.1 g/cm ³ or more, and in order to further increase the capacity of the battery, it is preferably 1.5 g/cm ³ or more, particularly preferably 1.7 g/cm ³ or more. In addition, the upper limit thereof is preferably 2 g/cm ³ or less.

In addition, examples of negative electrode active materials for lithium primary batteries include lithium metal and lithium alloys.

The structure of the lithium battery is not particularly limited, and coin-type batteries, cylindrical batteries, prismatic batteries, laminated batteries, etc. having a single-layer or multi-layer separator can be used.

The battery separator is not particularly limited, and single-layer or laminated microporous films, woven fabrics, and non-woven fabrics of polyolefins such as polypropylene and polyethylene can be used.

The lithium secondary battery of the present invention has excellent electrochemical characteristics over a wide temperature range when the end-of-charge voltage is 4.2V or higher, especially 4.3V or higher, and has good characteristics even at 4.4V or higher. Normally, the end-of-discharge voltage can be set to 2.8V or higher, and further can be set to 2.5V or higher, but the lithium secondary battery of the present invention can be set to 2.0V or higher. The current value is not particularly limited, but is usually used within a range of 0.1 to 30C. In addition, the lithium secondary battery of the present invention can be charged and discharged at -40 to 100°C, preferably at -10 to 80°C.

In the present invention, as a countermeasure against the increase in the internal pressure of the lithium battery, a method of providing a safety valve on the battery cover or providing a cutout on members such as the battery can and the gasket can also be adopted. In addition, as a safety measure to prevent overcharging, a current cutoff mechanism that senses the internal pressure of the battery and cuts off the current can be provided on the battery cover.

[Second power storage device (lithium ion capacitor)]

This electrical storage device is an electrical storage device that stores energy by intercalating lithium ions into a carbon material such as graphite as a negative electrode. These are called Lithium Ion Capacitors (LIC). Examples of the positive electrode include a positive electrode utilizing an electric double layer between an activated carbon electrode and an electrolytic solution, a positive electrode utilizing a doping/dedoping reaction of a π-conjugated polymer electrode, and the like. The electrolyte contains at least lithium salts such as LiPF ₆ .

Example

Examples I-1 to I-23, Comparative Examples I-1 to I-3

〔Manufacture of lithium-ion secondary battery〕

94% by mass of LiCoO ₂ and 3% by mass of acetylene black (conductive agent) were mixed, added to a solution obtained by dissolving 3% by mass of polyvinylidene fluoride (binder) in 1-methyl-2-pyrrolidone in advance, and Mix to make positive electrode mixture paste. The positive electrode mixture paste was coated on one side of an aluminum foil (current collector), dried, press-molded, and then cut to a predetermined size to obtain a positive electrode sheet. The density of the portion of the positive electrode other than the current collector was 3.6 g/cm ³ .

In addition, 95% by mass of artificial graphite (d ₀₀₂ =0.335nm, negative electrode active material) was added to a solution obtained by dissolving 5% by mass of polyvinylidene fluoride (binder) in 1-methyl-2-pyrrolidone in advance. and mixed to make negative electrode mixture paste. This negative electrode mixture paste was applied to one side of a copper foil (current collector), dried, press-molded, and then cut to a predetermined size to obtain a negative electrode sheet. The density of the portion of the negative electrode other than the current collector was 1.5 g/cm ³ . In addition, X-ray diffraction measurement was performed using this electrode sheet. As a result, the ratio of the peak intensity I(110) of the (110) plane of the graphite crystal to the peak intensity I(004) of the (004) plane [I(110)/ I(004)] is 0.1.

Then, they were stacked in the order of the positive electrode sheet obtained above, the separator made of microporous polyethylene film, and the negative electrode sheet obtained above, and the non-aqueous electrolyte solution of the composition described in Table 1 and Table 2 was added to make a laminated type. Battery.

〔Evaluation of high temperature cycle characteristics〕

Using the battery produced by the above method, charge it at a constant current and constant voltage of 1C in a constant temperature bath at 60°C for 3 hours until the end voltage is 4.3V, and then discharge it at a constant current of 1C until the discharge voltage is 3.0V. The above process is regarded as 1 cycle, and repeat it until 100 cycles are reached. Then, the discharge capacity retention rate after 100 cycles at 60° C. was obtained from the following formula.

Discharge capacity maintenance rate (%)=(discharge capacity after 100 cycles at 60°C/discharge capacity after 1 cycle)×100

<Evaluation of the amount of gas generated after 100 cycles>

The amount of gas generated after 100 cycles was measured by the Archimedes method. The amount of gas generation was based on the gas generation amount of Comparative Example 1 as 100%, and the relative gas generation amount was investigated.

＜Initial negative electrode thickness＞

The battery after one cycle was disassembled according to the method described above, and the thickness of the negative electrode at the initial stage was measured.

<Negative electrode thickness after cycle>

The battery after 100 cycles at 60° C. was decomposed according to the above method, and the thickness of the negative electrode after the high temperature cycle was measured.

＜Negative electrode thickness increase rate＞

The thickness increase rate of the negative electrode was obtained from the following formula.

Negative electrode thickness increase rate (%)=[(negative electrode thickness after 100 cycles at 60°C-initial negative electrode thickness)/initial negative electrode thickness]×100

In addition, the production conditions and battery characteristics of the battery are shown in Table 1.

Table 1

Table 2

Embodiment I-24, I-25 and comparative example I-4

The negative electrode active material used in Example I-2 and Comparative Example I-2 was changed, and silicon (single substance) (negative electrode active material) was used to produce a negative electrode sheet. Mix 40% by mass of silicon (single substance), 50% by mass of artificial graphite (d ₀₀₂ =0.335nm, negative electrode active material), and 5% by mass of acetylene black (conductive agent), and add them to 1-methyl-2-pyrrolidone The solution obtained by dissolving 5% by mass of polyvinylidene fluoride (binder) was mixed to prepare a negative electrode mixture paste. This negative electrode mixture paste is coated on one side of copper foil (collector), dried, press-molded, and then cut to a specified size to obtain negative electrode sheets. The same procedure as Example I-2 was used to fabricate a stacked battery and perform battery evaluation. The results are shown in Table 3.

table 3

Embodiment I-26, I-27 and comparative example I-5

The positive electrode active material used in Example I-2 and Comparative Example I-2 was changed, and LiFePO ₄ (positive electrode active material) covered with amorphous carbon was used to produce a positive electrode sheet. Mix 90% by mass of LiFePO ₄ covered by amorphous carbon, 5% by mass of acetylene black (conductive agent), and add to 5% by mass of polyvinylidene fluoride (binder) dissolved in 1-methyl-2-pyrrolidone in advance. % and mixed in the obtained solution to prepare a positive electrode mixture paste. The positive electrode mixture paste was applied to one side of the aluminum foil (collector), dried, press-molded, and then cut to a specified size to obtain a positive electrode sheet. The end-of-charge voltage during battery evaluation was set to 3.6V. Except that the end-of-discharge voltage was set to 2.0 V, a laminated battery was produced in the same procedure as in Example I-2 and Comparative Example I-2, and battery evaluation was performed. The results are shown in Table 4.

Table 4

The lithium secondary batteries of the above-mentioned Examples I-1 to I-23 and Comparative Examples I-1, Compared with the lithium secondary battery of Comparative Example I-2 when only 1,3-dioxane was added and Comparative Example I-3 when only 2-(diethoxyphosphoryl)ethyl acetate was added, the cycle The characteristics are all improved while suppressing an increase in the thickness of the negative electrode.

In addition, the amount of gas generated after the high-temperature cycle of the lithium secondary battery produced under the same conditions as in Example I-3, Comparative Example I-1, and Comparative Example I-2 was measured by the Archimedes method, and the result was : When the amount of gas generation in Comparative Example I-1 was set as 100%, it was 77% in Embodiment I-3, and 78% in Comparative Example I-2. Regarding the suppression of gas generation, even if the compound of general formula (I) was added Compounds are also equivalent.

From the above results, it was found that the effect of the present invention is unique to the case where the specific compound of the present invention is contained in the non-aqueous electrolytic solution in which the electrolyte salt is dissolved in the non-aqueous solvent.

In addition, from the comparison of Examples I-24, I-25 and Comparative Example I-4, and the comparison of Examples I-26, I-27 and Comparative Example I-5, it can be seen that when silicon (single substance) is used in the negative electrode, The same effect was also observed when lithium-containing olivine-type iron phosphate (LiFePO ₄ ) was used as the positive electrode. Therefore, it can be seen that the effect of the present invention does not depend on the effect of a specific positive electrode or negative electrode.

Furthermore, the non-aqueous electrolytic solutions of Examples I-1 to I-27 also have the effect of improving the discharge characteristics of lithium primary batteries in a wide temperature range.

Examples II-1 to II-13, Comparative Examples II-1 to II-2

〔Manufacture of lithium-ion secondary battery〕

94% by mass of LiCoO ₂ and 3% by mass of acetylene black (conductive agent) were mixed, added to a solution obtained by dissolving 3% by mass of polyvinylidene fluoride (binder) in 1-methyl-2-pyrrolidone in advance, and Mix to make positive electrode mixture paste. The positive electrode mixture paste was coated on one side of an aluminum foil (current collector), dried, press-molded, and then cut to a predetermined size to obtain a positive electrode sheet. The density of the portion of the positive electrode other than the current collector was 3.6 g/cm ³ .

In addition, 95% by mass of artificial graphite (d ₀₀₂ =0.335nm, negative electrode active material) was added to a solution obtained by dissolving 5% by mass of polyvinylidene fluoride (binder) in 1-methyl-2-pyrrolidone in advance. and mixed to make negative electrode mixture paste. This negative electrode mixture paste was applied to one side of a copper foil (current collector), dried, press-molded, and then cut to a predetermined size to obtain a negative electrode sheet. The density of the portion of the negative electrode other than the current collector was 1.5 g/cm ³ . In addition, X-ray diffraction measurement was performed using this electrode sheet. As a result, the ratio of the peak intensity I(110) of the (110) plane of the graphite crystal to the peak intensity I(004) of the (004) plane [I(110)/ I(004)] is 0.1.

Then, the positive electrode sheet obtained above, the separator made of microporous polyethylene film, and the negative electrode sheet obtained above were laminated in this order, and the non-aqueous electrolyte solution of the composition described in Table 5 was added to prepare a laminated battery.

〔Evaluation of high temperature cycle characteristics〕

Using the battery produced by the above method, charge it at a constant current and constant voltage of 1C in a constant temperature bath at 60°C for 3 hours until the end voltage is 4.3V, and then discharge it at a constant current of 1C until the discharge voltage is 3.0V. The above process is regarded as 1 cycle, and repeat it until 100 cycles are reached. Then, the discharge capacity retention rate after 100 cycles at 60° C. was obtained from the following formula.

Discharge capacity maintenance rate (%)=(discharge capacity after 100 cycles at 60°C/discharge capacity after 1 cycle)×100

<Evaluation of the amount of gas generated after 100 cycles>

The amount of gas generated after 100 cycles was measured by the Archimedes method. The amount of gas generation was based on the gas generation amount of Comparative Example 1 as 100%, and the relative gas generation amount was investigated.

＜Initial negative electrode thickness＞

The battery after one cycle was disassembled according to the method described above, and the thickness of the negative electrode at the initial stage was measured.

<Negative electrode thickness after cycle>

The battery after 100 cycles at 60° C. was decomposed according to the above method, and the thickness of the negative electrode after the high temperature cycle was measured.

＜Negative electrode thickness increase rate＞

The thickness increase rate of the negative electrode was obtained from the following formula.

Negative electrode thickness increase rate (%)=[(negative electrode thickness after 100 cycles at 60°C-initial negative electrode thickness)/initial negative electrode thickness]×100

In addition, the production conditions and battery characteristics of the battery are shown in Table 5.

table 5

Example II-14 and Comparative Example II-3

The negative electrode active material used in Example II-2 and Comparative Example II-2 was changed, and silicon (simple substance) (negative electrode active material) was used to produce a negative electrode sheet. Mix 40% by mass of silicon (single substance), 50% by mass of artificial graphite (d ₀₀₂ =0.335nm, negative electrode active material), and 5% by mass of acetylene black (conductive agent), and add them to 1-methyl-2-pyrrolidone The solution obtained by dissolving 5% by mass of polyvinylidene fluoride (binder) was mixed to prepare a negative electrode mixture paste. This negative electrode mixture paste is coated on one side of copper foil (collector), dried, press-molded, and then cut to a specified size to obtain negative electrode sheets. In the same procedure as Example II-2, a stacked battery was fabricated and battery evaluation was performed. The results are shown in Table 6.

Table 6

Example II-15 and Comparative Example II-4

The positive electrode active material used in Example II-2 and Comparative Example II-2 was changed, and LiFePO ₄ (positive electrode active material) covered with amorphous carbon was used to produce a positive electrode sheet. Mix 90% by mass of LiFePO ₄ covered by amorphous carbon, 5% by mass of acetylene black (conductive agent), and add to 5% by mass of polyvinylidene fluoride (binder) dissolved in 1-methyl-2-pyrrolidone in advance. % of the obtained solution and mixed to make a positive electrode mixture paste. The positive electrode mixture paste was applied to one side of the aluminum foil (collector), dried, press-molded, and then cut to a specified size to obtain a positive electrode sheet. The end-of-charge voltage during battery evaluation was set to 3.6V. Except that the end-of-discharge voltage was set to 2.0 V, a laminated battery was produced in the same procedure as in Example II-2 and Comparative Example II-2, and battery evaluation was performed. The results are shown in Table 7.

Table 7

The lithium secondary batteries of the above-mentioned Examples II-1 to II-13 and Comparative Examples II-1, Compared with the lithium secondary battery of Comparative Example II-2 in which only 1,3-dioxane was added, the cycle characteristics were all improved, and the increase in the thickness of the negative electrode was suppressed.

In addition, the lithium secondary batteries produced under the same conditions as in Example II-3, Example II-9, Comparative Example II-1, and Comparative Example II-2 after high-temperature cycles were measured by the Archimedes method. As a result, when the gas generation amount of Comparative Example II-1 was set to 100%, Example II-3 was 80%, Example II-9 was 79%, and Comparative Example II-2 was 81%. , Regarding the suppression of gas generation, even if the compound of the general formula (I) is added, it is equivalent.

From the above results, it was found that the effect of the present invention of reducing the increase rate of the electrode thickness is unique to the non-aqueous electrolytic solution in which the electrolyte salt is dissolved in the non-aqueous solvent containing the specific compound of the present invention.

In addition, from the comparison of Example II-14 and Comparative Example II-3, and the comparison of Example II-15 and Comparative Example II-4, it can be seen that when silicon (single substance) is used for the negative electrode, lithium-containing olivine-type phosphoric acid is used for the positive electrode. The same effect was also observed in the case of iron salt (LiFePO ₄ ). Therefore, it can be seen that the effect of the present invention does not depend on the effect of a specific positive electrode or negative electrode.

Furthermore, the non-aqueous electrolytic solutions of Examples II-1 to II-15 also have the effect of improving the discharge characteristics of lithium primary batteries in a wide temperature range.

Embodiment III-1～III-8

〔Manufacture of lithium-ion secondary battery〕

According to the same procedure as in Example I-1, a positive electrode sheet and a negative electrode sheet were produced, and they were stacked in the order of the positive electrode sheet, the microporous polyethylene film separator, and the negative electrode sheet, and the ingredients of the composition recorded in Table 8 were added. Non-aqueous electrolyte, making laminated batteries.

High-temperature cycle characteristics were evaluated in the same manner as in Example I-1.

Table 8 shows the production conditions and battery characteristics of the battery.

Table 8

The lithium secondary batteries of the above-mentioned Examples III-1 to III-8 and the above-mentioned lithium secondary batteries when the 1,3-dioxane of the present invention and the compound used in combination with 1,3-dioxane are not added to the non-aqueous electrolytic solution Compared with the lithium secondary battery of Comparative Example I-1 and Comparative Example I-2 in which only 1,3-dioxane was added, the cycle characteristics were improved, and the increase in the thickness of the negative electrode was suppressed.

In addition, the amount of gas generated after the high-temperature cycle of the lithium secondary battery produced by the Archimedes method under the same conditions as Example III-2, the above-mentioned Comparative Example I-1, and the above-mentioned Comparative Example I-2 was as follows: : When the gas generation amount of Comparative Example I-1 was set as 100%, Example III-2 was 76%, and the above-mentioned Comparative Example I-2 was 78%. Compounds used in combination with dioxane are also equivalent.

From the above results, it was found that the effect of the present invention is unique to the case where the specific compound of the present invention is contained in the non-aqueous electrolytic solution in which the electrolyte salt is dissolved in the non-aqueous solvent.

Furthermore, the non-aqueous electrolytic solutions of Examples III-1 to III-8 also have the effect of improving the discharge characteristics of lithium primary batteries in a wide temperature range.

Industrial Utilization Possibility

An electrical storage device using the nonaqueous electrolytic solution of the present invention is useful as an electrical storage device such as a lithium secondary battery having excellent electrochemical characteristics over a wide temperature range.

Claims (13)

1. a kind of nonaqueous electrolytic solution, it is characterised in that it is the nonaqueous electrolytic solution that electrolytic salt is dissolved with nonaqueous solvents, non- Containing 1, the 3- dioxs of 0.001~5 mass % in water electrolysis liquid, and under being selected from further containing 0.001~5 mass % State cyclic sulfonic acid ester compound that the phosphate compound, logical formula (II) that logical formula (I) represents represent and containing with allylic hydrogen Side chain cyclic acid anhydride at least one,

The cyclic acid anhydride contains cyclic acid anhydride main body and the side chain with the allylic hydrogen being bonded with the cyclic acid anhydride main body, ring Shape acid anhydrides main body is succinyl oxide,

In formula, R¹And R²After separately representing that carbon number is 1~6 alkyl or at least one hydrogen atom is replaced by halogen atom Carbon number be 1~6 haloalkyl, R³Represent that carbon number is 1~6 alkyl, the alkenyl that carbon number is 2~6 Or the alkynyl that carbon number is 3~6, R⁴And R⁵Separately represent hydrogen atom, halogen atom or the alkane that carbon number is 1~4 Base,

In formula, R⁶And R⁷The carbon number that separately representing hydrogen atom, at least one hydrogen atom can be replaced by halogen atom is 1 ~6 alkyl or halogen atom, X represents-CH (OR⁸)-or-C (=O)-, R⁸Represent formoxyl, the alkane that carbon number is 2~7 Base carbonyl, carbon number are that 3~7 alkenyl carbonyl, the alkynylcarbonyl groups that carbon number is 3~7 or carbon number is 7~13 Aryl carbonyl, R⁸At least one hydrogen atom can also be replaced by halogen atom.

2. nonaqueous electrolytic solution according to claim 1, wherein, the phosphate compound that logical formula (I) is represented is selected from 2- (diethoxy phosphoryl) methyl acetate, 2- (dimethoxyphosphoryl) acetic acid 2- propynyl esters, 2- (diethoxy phosphoryl) Ethyl acetate, 2- (diethoxy phosphoryl) acetic acid 2- propylenes, 2- (diethoxy phosphoryl) acetic acid 2- propynyl esters, 2- (dimethoxyphosphoryl) propionic acid 2- propynyl esters, 2- (diethoxy phosphoryl) propionic acid 2- propynyl esters, 2- (diethoxies Base phosphoryl) -2- methylfluoracetates, 2- (diethoxy phosphoryl) -2- ethyl fluoroacetates, 2- (diethoxy phosphinylidynes Base) -2- fluoroacetic acid 2- propylenes, 2- (diethoxy phosphoryl) -2- fluoroacetic acid 2- propynyl esters, 2- (diethoxies Phosphoryl) -2,2- methyl difluoroacetates, 2- (diethoxy phosphoryl) -2,2- ethyl difluoros, 2- (diethoxies Base phosphoryl) -2,2- difluoroacetic acid 2- propylenes and 2- (diethoxy phosphoryl) -2,2- difluoroacetic acid 2- propine At least one in ester.

3. nonaqueous electrolytic solution according to claim 1, wherein, the cyclic sulfonic acid ester compound that logical formula (II) is represented is to be selected from 2,2- titanium dioxide -1,2- oxathiolane -4- alcohol acetic esters and 5,5- dimethyl -1,2- oxathiolanes - 4- ketone 2, at least one in 2- dioxide.

4. nonaqueous electrolytic solution according to claim 1, wherein, the succinyl oxide containing the side chain with allylic hydrogen is choosing From 2- allyl succinic anhydrides, 2- (1- amylene -3- bases) succinyl oxide, 2- (1- hexene -3- bases) succinyl oxide, 2- (1- teracrylic acids-yl) succinyl oxide, 2- (1- octene -3- bases) succinyl oxide, 2- (1- nonene -3- bases) amber Amber acid anhydrides, 2- (3- butene-2s-yl) succinyl oxide, 2- (2- methacrylics) succinyl oxides and 2- (3- methyl- 3- butene-2s-yl) at least one in succinyl oxide.

5. nonaqueous electrolytic solution according to claim 1, wherein, nonaqueous solvents contains at least one cyclic carbonate.

6. nonaqueous electrolytic solution according to claim 5, wherein, cyclic carbonate is selected from ethylene carbonate, polypropylene carbonate Ester, carbonic acid 1,2- butylenes, carbonic acid 2 are fluoro- 1, the 3- dioxolane -2- ketone of 3- butylenes, 4-, trans or suitable Formula -4, fluoro- 1, the 3- dioxolane -2- ketone of 5- bis-, vinylene carbonate, vinyl ethylene carbonate and 4- second Alkynyl -1, one or two or more kinds in 3- dioxolane -2- ketone.

7. nonaqueous electrolytic solution according to claim 1, wherein, nonaqueous solvents further contains chain ester.

8. nonaqueous electrolytic solution according to claim 7, wherein, chain ester is selected from asymmetric linear carbonate, Symmetric Chain One or two or more kinds in shape carbonic ester and chain carboxylate, the asymmetric linear carbonate be selected from methyl ethyl carbonate, Asymmetric linear carbonate in methyl propyl carbonate, methyl isopropyl ester, carbonic acid first butyl ester and ethyl propyl carbonic acid ester, it is described symmetrical Linear carbonate is selected from the symmetrical chain carbonic acid in dimethyl carbonate, diethyl carbonate, dipropyl carbonate and dibutyl carbonate Ester.

9. nonaqueous electrolytic solution according to claim 1, wherein, electrolytic salt contains selected from LiPF₆、LiBF₄、LiPO₂F₂、 Li₂PO₃F、LiSO₃F、LiN(SO₂F)₂、LiN(SO₂CF₃)₂、LiN(SO₂C₂F₅)₂, double [oxalate-O, O '] lithium borates, difluoro it is double The lithium salts of one or two or more kinds in [oxalate-O, O '] lithium phosphate and tetrafluoro [oxalate-O, O '] lithium phosphate.

10. nonaqueous electrolytic solution according to claim 9, wherein, the concentration of lithium salts relative to nonaqueous solvents be 0.3~ 2.5M。

11. a kind of electric energy storage devices, it is characterised in that it is that possess positive pole, negative pole and be dissolved with electrolytic salt in nonaqueous solvents Nonaqueous electrolytic solution electric energy storage device, containing 1, the 3- dioxs of 0.001~5 mass % in nonaqueous electrolytic solution, and further contain There is the cyclic sulfonic acid ester chemical combination that the phosphate compound represented selected from logical formula (I) of 0.001~5 mass %, logical formula (II) are represented At least one in thing and the cyclic acid anhydride containing the side chain with allylic hydrogen,

The cyclic acid anhydride contains cyclic acid anhydride main body and the side chain with the allylic hydrogen being bonded with the cyclic acid anhydride main body, ring Shape acid anhydrides main body is succinyl oxide,

In formula, R¹And R²After separately representing that carbon number is 1~6 alkyl or at least one hydrogen atom is replaced by halogen atom Carbon number be 1~6 haloalkyl, R³Represent that carbon number is 1~6 alkyl, the alkenyl that carbon number is 2~6 Or the alkynyl that carbon number is 3~6, R⁴And R⁵Separately represent hydrogen atom, halogen atom or the alkane that carbon number is 1~4 Base,

In formula, R⁶And R⁷The carbon number that separately representing hydrogen atom, at least one hydrogen atom can be replaced by halogen atom is 1 ~6 alkyl or halogen atom, X represents-CH (OR⁸)-or-C (=O)-, R⁸Represent formoxyl, the alkane that carbon number is 2~7 Base carbonyl, carbon number are that 3~7 alkenyl carbonyl, the alkynylcarbonyl groups that carbon number is 3~7 or carbon number is 7~13 Aryl carbonyl, R⁸At least one hydrogen atom can also be replaced by halogen atom.

12. electric energy storage devices according to claim 11, wherein, the active material of positive pole is containing selected from cobalt, manganese and nickel One or two or more kinds with the metal composite oxide of lithium or be to contain the one kind or two selected from iron, cobalt, nickel and manganese Phosphate of olivine type containing lithium more than kind.

13. electric energy storage device according to claim 11 or 12, wherein, the active material of negative pole contains selected from lithium metal, lithium Alloy, can be embedded in and the carbon material of removal lithium embedded, tin, tin compound, silicon, silicon compound and lithium titanate compound in one kind or More than two kinds.